1. Field of the Invention
The present invention relates to an in-vehicle device that has a display unit and performs wireless communication with a portable terminal device, and a wireless communication system.
2. Description of the Related Art
Along with diffusion of car navigation systems using a global positioning system (GPS), many vehicles come to have in-vehicle devices with a navigation function incorporated therein. To respond to user's desire for multiple functions in in-vehicle devices, in-vehicle devices have become remarkably multifunctional.
For example, in many cases, in-vehicle devices include functions such as a television receiving function, a compact disc (CD) reproduction function, a digital versatile disk (DVD) reproduction function, in addition to a navigation function. However, multifunctional in-vehicle devices incur a high cost of the devices, and high price is not preferable for users.
Meanwhile, portable terminal devices such as mobile telephones have come to have a navigation function and a music reproducing function while maintaining lower price. Portable terminal devices having a short-distance wireless communication function such as Bluetooth® have also come into popular use. Therefore, there are approaches to use functions of a portable terminal device in an in-vehicle device, by linking the portable terminal device and the in-vehicle device by the short-distance wireless communication function. With this arrangement, it becomes possible to reduce the price of in-vehicle devices.
For example, Japanese Patent Application Laid-open No. 2003-244343 discloses a technique, according to which a display screen to be displayed on a screen of a portable terminal device is transmitted to an in-vehicle device, and the display screen generated by the portable terminal device is displayed on a display of the in-vehicle device.
However, in the conventional technique disclosed in Japanese Patent Application Laid-open No. 2003-244343 or the like, a user operation of transmitting information to an in-vehicle device is required on the portable terminal device side and a user operation of displaying information sent from the portable terminal device on the display is required on the in-vehicle device side. Therefore, a certain degree of skill is required for controlling and linking the portable terminal device and the in-vehicle device, and this has caused inconveniences.
Specifically, a user who wishes to use a portable terminal device and an in-vehicle device in cooperation with each other in a vehicle needs to perform such operations that a wireless function such as Bluetooth is activated on both devices to transmit desired information to the in-vehicle device by specifying a destination by the portable terminal device and display received information on the in-vehicle device. Thus, to link both devices with each other, several operations need to be performed, and it is not easy for users who are not used to using such devices (elderly people, for example). Therefore, it is thought that linking a portable terminal device and an in-vehicle device according to conventional techniques is not convenient.